Method and apparatus for inserting a flexible membrane into an eye

ABSTRACT

An instrument for inserting a flexible intraocular lens or other flexible membrane into an eye which includes a compressor for laterally compressing the lens into a small cross-sectional configuration to pass the lens through a narrow incision. The compressor includes retainers along the interior of the inserter to maintain the side edges of the lens in a substantially planar orientation during compression. The retainers preferably extend through the inserter to hold the lens during advancement toward the eye to prevent an uncontrolled rotation of the lens. A haptic guide may be placed through the distal end of the inserter to properly position the leading loop haptic of the lens.

This application is a division of application Ser. No. 08/721,349, filedSep. 26, 1996, now U.S. Pat. No. 5,944,725.

FIELD OF THE INVENTION

The present invention pertains to a method and apparatus for inserting aflexible intraocular lens or other flexible membrane into an eye.

BACKGROUND OF THE INVENTION

The natural crystalline lens of the eye plays a primary role in focusinglight onto the retina for proper vision. However, vision through thenatural lens may become impaired due to an injury, or due to theformation of a cataract caused by aging or disease. To restore vision,the natural lens is typically replaced with an artificial lens. Anartificial lens may also be implanted to make a refractive correction.

Many surgical procedures have been developed for removing the naturallens. Typically, a slender implement is inserted through a smallincision in the eye to contact the natural lens. The implement includesa cutting tip that is ultrasonically vibrated to emulsify the lens. Theemulsified fragments of the lens are then aspirated out of the eyethrough a passage provided in the cutting tip. The slender nature of theimplement enables extraction of the lens through a small incision in theeye. The use of a small incision over other procedures requiring a largeincision can lessen the trauma and complications experienced during thesurgery and postoperatively.

Because the incision required to remove the lens is small, thedevelopment of intraocular implants to replace the lens has been in thedirection of flexible implants that do not require any enlargement ofthe incision. An intraocular lens commonly includes a generally diskshaped optic which focuses Light on the retina and an outwardlyextending haptic portion for proper positioning of the optic within theeye. The flexible nature of the lens enables the lens to be folded andcompressed so as to occupy a smaller cross-sectional area for passagethrough the narrow incision and into the eye. Once inserted through theincision, the lens is permitted to expand to its original size andshape.

A number of devices have been developed to insert a flexible intraocularlens through a small incision in the eye. For example, U.S. Pat. No.4,681,102 to Bartell uses a hinged cartridge which closes about a lensto fold the lens into a narrower configuration. The cartridge is placedinto an inserter mechanism which advances the folded lens into the eye.The inserter, however, requires several components to be manipulated andassembled during the operation. U.S. Pat. No. 5,275,604 to Rheinish etal. pushes the lens through a narrowing lumen formed with grooves whichact to fold the lens into a smaller size as it is pushed toward the eye.The manufacture of spiraling grooves in a tapering lumen is difficult ifnot impossible to accomplish in a practical manner. In U.S. Pat. No.5,304,182 to Rheinish et al., a curling member is shifted laterally tofold the lens into a size small enough to pass through the narrowincision. However, no locking arrangement is provided to ensurecompletely closing of the curling member.

Moreover, while these devices function to reduce the cross-sectionalsize of the lens for insertion into the eye, they all require theopposing side edges of the lens to be folded over on themselves in orderto fit through the narrow incision. As a result, the lens must swingopen within the eye to regain its original shape and size. Suchunfolding causes the lens, and particularly the haptics, to be swung inan arc, and thus risks damaging the interior of the eye.

As the lens is released into the eye, the resiliency of the lens causesthe lens to open and resume its natural shape. However, the folding andpressing of the lens needed to pass the lens through the small incisionplaces a significant amount of inward pressure on the lens. As a result,the lens is frequently discharged from the inserter with considerableforce and velocity. This forceful, uncontrolled release of the lens alsoplaces the interior of the eye at risk of being injured.

Further, many inserters do not maintain control of the orientation ofthe lens as the lens is advanced into the eye. Consequently, the lensmay rotate or turn about a longitudinal axis as it is pushed through theinserter. Most lenses, however, are made to be set within the eye in aspecific orientation. Accordingly, such turning of the lens can resultin the lens being placed in the eye in an improper orientation.

SUMMARY OF THE INVENTION

The present invention pertains to a method and apparatus for inserting aflexible intraocular lens or other flexible membrane into an eye withoutthe above-noted risks associated with inserter devices of the past. Morespecifically, the present inserter maintains the substantially planarorientation of the opposing side edges of the lens as the lens islaterally compressed into a smaller cross-sectional configuration forinsertion through a narrow incision in the eye. Since the side edges ofthe lens are not folded over on themselves during compression, the lensdoes not swing open within the eye in order to regain its originalshape. As a result, the risk of a part of the lens striking and injuringan interior portion of the eye after release of the lens from theinserter is reduced.

In the preferred construction, retainers in the form of troughs areformed along the interior of the inserter to receive and maintain theside edges of the lens in a substantially planar orientation duringcompression. The troughs further extend through the inserter to hold thelens during advancement toward the eye to prevent an uncontrolledrotation of the lens. In this way, the lens is assured of beingdischarged in its proper orientation.

In another aspect of the invention, the inserter permits the lens toexpand prior to its release into the eye. In this way, the resilientforce which works to expand the compressed lens is dissipated prior tothe lens being discharged from the inserter. The lens can thus beimplanted into the eye in a controlled manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an instrument in accordance with thepresent invention.

FIG. 2 is a partial perspective view of the instrument with a compressorin a closed position.

FIG. 3 is a partial perspective view of the instrument with thecompressor removed.

FIG. 4 is a perspective view of the compressor.

FIG. 5 is a partial perspective view of the instrument with anintraocular lens at the free end of the instrument.

FIGS. 6A-6C are cross sectional views of the instrument taken along line6—6 in FIG. 1 with the compressor at different stages of compressing alens.

FIG. 6D is a partial cross sectional view of the instrument taken alongline 6—6 in FIG. 1 with the compressor in a closed position and the lensomitted.

FIG. 7 is a cross-sectional view taken along line 7—7 in FIG. 1.

FIG. 8 is a partial cross-sectional view of a second embodiment of aninstrument in accordance with the present invention illustrating thecompression of a lens.

FIG. 9 is a partial perspective view of a third embodiment of aninstrument in accordance with the present invention.

FIG. 10 is a partial top plan view of the third embodiment of theinstrument.

FIG. 11 is a partial perspective view of a fourth embodiment of aninstrument in accordance with the present invention.

FIG. 12 is a partial perspective view of a fifth embodiment of aninstrument in accordance with the present invention.

FIG. 13 is a partial cross-sectional view of the fifth embodiment of theinstrument.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention pertains to an inserter 10 (FIGS. 1-7) forimplanting a flexible intraocular lens or other flexible membrane intoan eye. An intraocular lens typically includes an optic and a hapticportion, although the haptic portion is occasionally omitted. The hapticportion can take many forms, but is usually composed of plate or loophaptics. For illustration purposes only, this application will describethe use of inserter 10 with a lens 12 provided with a pair of loophaptics 16 a, 16 b (FIGS. 1, 5, 6, 8 and 10). Inserter 10, however, isusable with a wide variety of lenses or other flexible membranes.

Lens 12 includes an optic 14 and a pair of loop haptics 16 a, 16 b(FIGS. 1, 5, 6, 8 and 10). The haptics are thin, wire-like, resilientmembers which extend from diametrically opposed sides 18 a, 18 b ofoptic 14 in opposite directions. Haptics 16 a, 16 b are arcuate in shapesuch that their free ends 20 point generally back toward optic 14.

In the preferred construction, inserter 10 includes a tubular member 22for receiving and directing the lens into an eye (FIGS. 1-3 and 5-7).The tubular member 22 generally includes a body 24, a compressingstation 26, and a cannula 28 (FIGS. 1-3 and 5). Body 24, cannula 28, anda support portion 29 of compressing station 26 are preferably formed asa unitary molded member, although an integral assembly of plural partscould also be used.

At the proximal end of member 22, body 24 forms a rearwardly openingpassage which is adapted to receive a plunger 32 (FIG. 1). The plungerincludes a base 34 matingly received in body 24 and a shaft 36 (FIG. 10)which extends forward to engage and push lens 12 into an eye. As isknown in the industry, the base of plunger 32 is shaped to preventrotation of the plunger relative to tubular member 22. For example, thebase 34 and the passage may have complementary non-circular shapes or akey and keyway construction. In addition, while plunger 32 is preferablyadvanced manually through body 24, a motor or other driving arrangementcould be used to move the plunger.

Compressing station 26 includes an opening 38 in axial alignment withthe passage of body 24 for receiving, compressing and directing lens 12into cannula 28 (FIGS. 1-6D). Compressing station 26 includes a support29 molded with body 24 and cannula 28, and a compressor 40 which ismounted for movement in the support. Support 29 includes a generallyU-shaped wing 42 provided with an elongate shelf 44 and a pair of arms46. The arms and shelf collectively define a lateral channel or guideway48 into which compressor 40 is moveably received. A lip 50 formed alongthe free end of each arm 46 retains compressor 40 against shelf 44 andthereby restricts the compressor to a lateral motion in channel 48. Theinner end of each lip 50 defines a shoulder 55 over which a latch 56from compressor 40 is received to lock the compressor in place for theoperation. An additional abutting flange (not shown) or other knownconstruction may also be included to prevent compressor 40 from beingremoved from channel 48.

Compressor 40 includes a pair of side faces 61 which are adapted to bematingly received within channel 48, and an inner sidewall 62 which isadapted to engage and compress the lens 12. A cover flange 64 projectsbeyond sidewall 62 to overlie the opposite side 58 of support 29 andenclose opening 38 when the compressor is moved inward (FIGS. 2 and5-6D). Latches 56 are positioned along each side of compressor 40 abovecover flange 64. Latches 56 have ramps 65 which ease the inward movementof the compressor, and abutting faces 68 which snap out to engageshoulders 55 and lock compressor 40 in its closed position with support29. The compressor is preferably irrevocably locked in place for asingle use, but could be constructed to permit release if desired.Ledges 70 underlie lips 50 to guide the lateral movement of compressor40 within channel 48 (FIGS. 1 and 4).

Compressor 40 is laterally movable between an open position whereincover flange 64 is spaced from side 58 of support 29 (FIG. 1), and aclosed position wherein cover flange 64 overlies side 58 and latches 56engage shoulders 55 (FIGS. 2, 5, 6C and 6D). In the open position, a gap66 is defined between cover flange 64 and side 58 for the placing of alens 12 into opening 38 (FIG. 1). The lens can be placed within tubularmember 22 prior to shipment or by medical personnel at the time ofsurgery. In the closed position, sidewall 62 of compressor 40 is placedinto an opposed relation with a sidewall 60 of side 58, and in axialalignment with the inner ends 52 of arms 46 (FIGS. 2, 5, 6C and 6D).

Each sidewall 60, 62 is provided with a retainer which receives andholds the opposite side edges 18 a, 18 b of optic 14 to prevent the sideedges from being folded over or turning when compressor 40 is moved toits closed position (FIGS. 4 and 6A-6D). More specifically, the sideedges 18 a, 18 b of the lens are oriented generally along a centralplane. The retainers function to hold and support the side edges of thelens in this generally planar relationship during compression of thelens. Since the side edges of the lens are not folded over onthemselves, the lens expands laterally within the eye without a swingingmotion. This lateral shifting of the side edges for expansion of thelens is safer and less likely to contact and damage the interior of theeye than a swinging motion to unfold the lens. In the preferredconstruction, retainers are formed as troughs 68, 70. Nevertheless, theretainers could have other constructions so long as they maintain thesides of the lens in a substantially planar orientation and permitadvancement of the lens into the eye.

Troughs 68, 70 are preferably flanked by inclined segments 72-75 whichsupport and compress the optic during inward movement of compressor 40,and which help maintain the sides of lens 12 in troughs 68, 70 (FIGS.6A-6D). Sidewalls 60, 62 are spaced apart by upper and lower parallelsurfaces defined by cover flange 64 and shelf 44 to form an axialpassage 76 through which the lens is advanced by plunger 32.

As compressor 40 is moved inward, the side edges 18 a, 18 b of optic 14are received within troughs 68, 70 (FIG. 6A). Continued inward movementof the compressor causes the sides 18 a, 18 b to be snugly pushed intotroughs 68, 70 in order to prevent their release (FIG. 6B). Thismovement of compressor 40 also begins to laterally compress the lens.Although the lens will have a tendency to crumple slightly duringcompression, side edges 18 a, 18 b of the lens are retained in troughs68, 70 to maintain the edges 18 a, 18 b in a generally planarrelationship. Finally, when latches 56 are locked on shoulders 55, lens12 is in a compressed configuration between sidewalls 60, 62 (FIG. 6C).Inner ends 52 of arms 46 (FIG. 3) are also formed with surfaces whichare identical to sidewall 62 to form continuous walls for passage 76(FIG. 6D).

While flanking segments 72-75 can be identical mirror images to oneanother (see troughs 68 a, 70 a and segments 72 a-75 a of FIG. 8), theyare preferably asymmetrical to better orient the haptics for insertion(FIG. 6D). More specifically, troughs 68, 70 are each partially definedby upper and lower faces 80-83. One face 80, 83 of each trough 68, 70extends inward a greater distance than the opposing face 81, 82. Thelonger faces 80, 83 merge with arcuate flanking segments 72, 75. Theshorter faces 81, 82 terminate and intersect flanking segments 73, 74 atpoints closer to the outer faces 92, 94 of troughs 68, 70. While theintersections of faces 81, 82 with flanking segments 73, 74 arepreferably angular, they may also be rounded. In this particularconstruction, side edge 18 a with leading haptic 16 a is placed adjacentsidewall 60.

As compressor 40 is moved inward, the side edges 18 a, 18 b will bereceived into troughs 68, 70 (FIGS. 6A-6D). As lens 12 compresses, theasymmetric faces 80-83 will cause the lens to dip slightly about theshorter faces 81, 82, and create a slight twist in optic 14 so thatleading haptic 16 a tends to point in a downward direction. Thisdownward orientation of leading haptic 16 a will enable the surgeon tomore easily place the haptic within the capsular bag of the eye.Similarly, the trailing haptic 16 b is shifted to incline slightlyupward to avoid contact by plunger 32; that is, so that the free end 77of shaft 36 directly engages optic 14 (FIG. 10).

Alternatively, compressing station 26 b includes a support 29 b moldedwith body 24 b and cannula 28 b, and a pair of opposed compressors 40 b,41 b (FIGS. 9 and 10). The compressors are supported in a pair ofopposite slits 96 b formed in the sides of support 29 b for lateralmovement toward and away from each other. Compressors 40 b, 41 b haveinner sidewalls 60 b, 62 b which are preferably shaped as describedabove for sidewalls 60, 62; nevertheless, the sidewalls could besymmetrically formed as with sidewalls 60 a, 62 a. An opening 66 b isformed in the top of support 29 b to permit the placement of a lens 12.To prevent loss or outward bowing of the lens, a cover 101 b is hingedto support 29 b to overlie opening 66 b before closure of compressors 40b, 41 b. Latches (not shown) are provided to lock the compressors intheir closed positions.

Cannula 28 projects forwardly from the distal end of compressing station26 to direct lens 12 into an eye (FIGS. 1-3 and 5). Cannula 28preferably includes a proximal, funnel-shaped portion 103 which tapersto further compress the lens, and an elongate distal portion 105 whichdirects the compressed lens into an eye. Nevertheless, the cannula couldbe formed to have a uniform taper across its length or provided with notaper if, for example, the compressor(s) has a longer stroke to completethe desired compression of the lens.

An interior lumen 107, which extends through cannula 28, is axiallyaligned with passage 76 of compressing station 26 to form a continuousduct through which lens 12 is moved (FIG. 7). Lumen 107 is preferablydefined by sidewalls 109 provided with troughs 111 and upper and lowerflanking segments 113, 115 to match sidewalls 60, 62 of compressingstation 26. At the rear end 117 of proximal portion 103, troughs 111 arealigned with troughs 68, 70 (when compressor 40 is in the closedposition) to form a continuous retention of side edges 18 a, 18 b as thelens is advanced into the eye. The sidewalls 109 of proximal portion 103preferably converge forwardly at an angle of about 7° to furthercompress the lens as it is advanced through cannula 28. As noted above,troughs 111 continue to hold the side edges 18 a, 18 b of optic 14 asthe lens passes through cannula 28 to maintain the generally planarorientation of the side edge of the lens and to prevent turning of thelens during its advancement through lumen 107.

Distal portion 105 of cannula 28 is an elongate, slender tube to permitentry of the inserter 10 through a narrow incision (not shown). Whilethe sidewalls 109 in distal portion 105 are angularly oriented to thesidewalls 109 in proximal portion 103, they are identical with respectto the formation of the troughs 111 and flanking segments 113, 115.Troughs and flanking segments therefore continue through distal portion105 to properly support and hold lens 12 throughout its passage throughcannula 28. Although the sidewalls 109 in distal portion 105 preferablyconverge slightly for molding purposes, they could be formed. withparallel walls.

The free end 119 of cannula 28 is preferably provided with a pair ofopposed longitudinal slits 121 in troughs 111 (FIGS. 1-3, 5 and 7).Slits 121 are wide enough to permit sides 18 a, 18 b of optic 14 toextend outward beyond the exterior sides 123 of cannula 28. The slitstherefore permit lateral expansion of the lens prior to its release intothe eye. As a result, the natural resilient force which biases the lensto assume its original uncompressed shape is dissipated in thecontrolled environment of the cannula. The lens is thus not releasedwith any velocity as in many prior art inserters.

Further, since the lens is compressed without folding the side edgesover on themselves, expansion of the lens requires only an outward,lateral movement of the lens. The lens experiences no swinging of theoptic or haptics within the eye which risks damaging the interior of theeye. Slits 121 also continue to hold optic 14 and prevent turning of thelens so that implantation of the lens in the proper orientation isensured. Accordingly, insertion of the lens with inserter 10 provides asafer implantation procedure than heretofore realized.

A haptic guide 125 is optionally provided in the front of inserter lob(or 10) to ensure the proper positioning of the leading loop haptic 16 a(see FIGS. 9 and 10). Haptic guide 125 includes a generally flat pulltab 127 and a slender rod 129 projecting from the pull tab. Rod 129 issized to be received rearwardly within lumen 107 from free end 119. Ahook 131 or other shoulder element is formed on the free end 133 of rod129. In use, rod 129 is fully inserted into lumen 107 so that hook 131is visible through the gap 66 b in compressing station 26 b. As the lensis loaded into the opening, leading haptic 16 a is looped over hook 131.Pull tab 127 is manually pulled forward to remove rod 129 from inserter10. Removal of haptic guide 125 can be performed before or after closureof compressors 40 b, 41 b or cover 101 b. As the rod moves forward, hook131 engages and pulls haptic 16 a forward so that its free end ispositioned into lumen 107. This pulling of the haptic tends to partiallystraighten haptic 16 a to point generally in the direction of the lens'movement. This positioning of the haptic reduces the risk of the leadinghaptic 16 a being drawn back and becoming lodged around the optic duringinsertion. Ribs 135 or other gripping surface are preferably formed onpull tab 127 to enhance the manual grasping of the component.

As is common with lens insertion procedures, a viscoelastic or otherlubricant material is injected into the inserter to ease the movement ofthe lens into the eye. The lubricant can be injected prior to closure ofcompressor 40 (or cover 101 b). Alternatively, cover flange 64 c (or awall of the tubular member) can be provided with an aperture 137 throughwhich the lubricant can be injected after the closing of compressor 40 c(FIG. 11). Also, a lubricant pouch 139 filled with a lubricant 141 canbe attached to the exterior of cover flange 64 d (FIGS. 12 and 13). Abarb can be provided adjacent the aperture to puncture the plastic pouchto permit release of the lubricant into the passage upon the applicationof pressure on the pouch. Alternatively, pouch 139 includes a frangibleportion (e.g., by scoring) which is aligned with a small aperture 143 incover flange 64. Once the compressor is moved to its closed position, auser may apply pressure to lubricant pouch 139 to break open the pouchand dispense the lubricant into opening 38 through aperture 143. Also,cover flange 64 c can cooperate with a fixed cutter (not shown) to openpouch 139 upon the closure of compressor 40 c to permit the discharge ofthe lubricant through aperture 143 and into the passage.

The above discussion concerns the preferred embodiments of the presentinvention. Various other embodiments as well as many changes andalterations may be made without departing from the spirit and broaderaspects of the invention as defined in the claims. For example, thecompressing station, with or without the cannula, can be formed as aseparable cartridge for compressing the lens. The cartridge can then beplaced within an injector device for insertion of the lens into the eyeafter the lens has been compressed. As is common with cartridges,flanges or other structures could be included to facilitate manipulationof the cartridge and prevent turning of the cartridge in the injectordevice. Also, the central portion of the optic 14 could be manipulatedinto a U-shape, W-shape, or other folded configuration as opposed to thedirect compression of the preferred embodiment. So long as the sideedges of the lens are maintained in a generally planar orientation thelens will still expand with a lateral shifting motion which avoids thebroad swinging of the outer edges and haptics within the eye.

What is claimed is:
 1. An instrument for inserting a lens into an eye, the lens including an optic, a leading haptic and a trailing haptic, said instrument comprising a tubular unit including a passage having a distal opening through which the lens is directed into the eye, and a haptic guide including a rod received within said passage through said distal opening, said rod having an end to engage the leading haptic, said end being movable in said passage toward said distal opening and said end at least partially straightening the leading haptic during engagement of said end with the leading haptic and with movement of said end in the direction of advancement of the lens, wherein said end has having a shoulder to engage and pull the leading haptic in said passage.
 2. An instrument in accordance with claim 1 in which said haptic guide further includes a pull tab for manual grasping and pulling said haptic guide from said passage. 